An efficient ionic liquids (ILs) recycle technology will increase the economic viability of lignocellulosic biorefinery. The availability of recycling 1-butyl-3-methylimidazolium chloride for rice straw (RS) pretreatment was conducted. The kosmotropic salt K₃PO₄ (TKP) solution was used as antisolvent for cellulose precipitation and forming a three-phase system consisting of biomass, ILs-rich, and salt-rich phases. The upper ILs phase and the bottom TKP phase were recycled without additional purification, which significantly simplifies the process for recovering ILs. Subsequently, the RS pretreated with multiple reusing ILs (RPRS) were investigated by components analysis, structure evolution, enzymatic hydrolysis, and fermentation experiments. The results showed that unpurified reusing ILs led to further delignification and improvement of enzyme accessibility of the pretreated RS. The reducing sugar yield of RS pretreated with 8th reusing IL (8th RPRS) could still reach 98.9%, and the ethanol and succinic acid concentrations achieved 91.9 and 29.3 g/L by simultaneous saccharification and cofermentation. The present study demonstrated that the ILs recovered by phase-separation process could be used for RS pretreatment, and achieving high titer ethanol fermentation.

中文翻译：

---

低成本生物精炼的相分离工艺用回收离子液体预处理稻草

一种高效的离子液体 (IL) 回收技术将提高木质纤维素生物精炼厂的经济可行性。进行了回收 1-丁基-3-甲基咪唑氯化物用于稻草 (RS) 预处理的可用性。亲液盐 K ₃ PO ₄(TKP) 溶液用作纤维素沉淀的反溶剂，并形成由生物质、富含离子液体和富含盐的相组成的三相系统。上部 IL 相和底部 TKP 相无需额外纯化即可循环使用，这显着简化了回收 IL 的过程。随后，通过成分分析、结构演化、酶水解和发酵实验研究了多次重复利用 ILs (RPRS) 预处理的 RS。结果表明，未纯化的重复使用 IL 导致进一步脱木素并提高了预处理 RS 的酶可及性。经第8次重复利用IL(8th RPRS)预处理的RS的还原糖产率仍可达到98.9%，同时糖化和共发酵的乙醇和琥珀酸浓度分别达到91.9和29.3 g/L。